Long-lasting pigmentation of human skin, a new look at an overlooked response to UV.
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ABSTRACT:
SUBMITTER: Coelho SG
PROVIDER: S-EPMC2709973 | biostudies-literature | 2009 Apr
REPOSITORIES: biostudies-literature
Publications
Long-lasting pigmentation of human skin, a new look at an overlooked response to UV.
Coelho Sergio G SG Zhou Yanchun Y Bushar Harry F HF Miller Sharon A SA Zmudzka Barbara Z BZ Hearing Vincent J VJ Beer Janusz Z JZ
Pigment cell & melanoma research 20090217 2
Similar Datasets
Project description:To test whether there is a photoprotective benefit after different types of suberythemal repetitive UV, a 1.5 MED challenge dose was applied 1 week after the initial 2 weeks of repetitive irradiation. To determine what different mechanisms and/or factors might be involved in physiological pigmentary responses of the skin to different types of UV, we used whole human genome microarrays and immunohistochemical analyses to characterize human skin in situ to examine how melanocyte-specific proteins and paracrine melanogenic factors are regulated by repetitive exposure to suberythemal doses of different types of UV (UVA and/or UVB). Seven volunteers with skin type II-III were irradiated with UVA, UVB or UVA+UVB radiation for 2 weeks (5 times per week, 10 times total) after preliminary determination of their MEDs. A UVA+UVB challenge dose of 1.5X the MED was applied 1 week later. Biopsies were taken before the challenge dose, immediately after the challenge dose, 4 days after the challenge, and 15 weeks after the challenge.
2014-12-12 | E-GEOD-56754 | biostudies-arrayexpress
Project description:Human skin colour, ie pigmentation, differs widely among individuals, as do their responses to various types of ultraviolet radiation (UV) and their risks of skin cancer. In some individuals, UV-induced pigmentation persists for months to years in a phenomenon termed long-lasting pigmentation (LLP). It is unclear whether LLP is an indicator of potential risk for skin cancer. LLP seems to have similar features to other forms of hyperpigmentation, eg solar lentigines or age spots, which are clinical markers of photodamage and risk factors for precancerous lesions. To investigate what UV-induced molecular changes may persist in individuals with LLP, clinical specimens from non-sunburn-inducing repeated UV exposures (UVA, UVB or UVA + UVB) at 4 months post-exposure (short-term LLP) were evaluated by microarray analysis and dataset mining. Validated targets were further evaluated in clinical specimens from six healthy individuals (three LLP+ and three LLP-) followed for more than 9 months (long-term LLP) who initially received a single sunburn-inducing UVA + UVB exposure. The results support a UV-induced hyperpigmentation model in which basal keratinocytes have an impaired ability to remove melanin that leads to a compensatory mechanism by neighbouring keratinocytes with increased proliferative capacity to maintain skin homeostasis. The attenuated expression of SOX7 and other hemidesmosomal components (integrin α6β4 and plectin) leads to increased melanosome uptake by keratinocytes and points to a spatial regulation within the epidermis. The reduced density of hemidesmosomes provides supporting evidence for plasticity at the epidermal-dermal junction. Altered hemidesmosome plasticity, and the sustained nature of LLP, may be mediated by the role of SOX7 in basal keratinocytes. The long-term sustained subtle changes detected are modest, but sufficient to create dramatic visual differences in skin colour. These results suggest that the hyperpigmentation phenomenon leading to increased interdigitation develops in order to maintain normal skin homeostasis in individuals with LLP.
| S-EPMC4398603 | biostudies-literature
Project description:To test whether there is a photoprotective benefit after different types of suberythemal repetitive UV, a 1.5 MED challenge dose was applied 1 week after the initial 2 weeks of repetitive irradiation. To determine what different mechanisms and/or factors might be involved in physiological pigmentary responses of the skin to different types of UV, we used whole human genome microarrays and immunohistochemical analyses to characterize human skin in situ to examine how melanocyte-specific proteins and paracrine melanogenic factors are regulated by repetitive exposure to suberythemal doses of different types of UV (UVA and/or UVB).
2014-12-12 | GSE56754 | GEO
Project description:The skin of an organism is affected by various environmental factors and fights against aging stress via mechanical and biochemical responses. Photoaging induced by ultraviolet B (UVB) irradiation is common and is the most vital factor in the senescence phenotype of skin, and so, suppression of UVB stress-induced damage is critical. To lessen the UVB-induced hyperimmune response and hyperpigmentation, we investigated the ameliorative effects of intense pulsed light (IPL) treatment on the photoaged phenotype of skin cells. Normal human epidermal keratinocytes and human epidermal melanocytes were exposed to 20 mJ/cm2 of UVB. After UVB irradiation, the cells were treated with green (525–530 nm) and yellow (585–592 nm) IPL at various time points prior to the harvest step. Subsequently, various signs of excessive immune response, including expression of proinflammatory and melanogenic genes and proteins, cellular oxidative stress level, and antioxidative enzyme activity, were examined. We found that IPL treatment reduced excessive cutaneous immune reactions by suppressing UVB-induced proinflammatory cytokine expression. IPL treatment prevented hyperpigmentation, and combined treatment with green and yellow IPL synergistically attenuated both processes. IPL treatment may exert protective effects against UVB injury in skin cells by attenuating inflammatory cytokine and melanogenic gene overexpression, possibly by reducing intracellular oxidative stress. IPL treatment also preserves antioxidative enzyme activity under UVB irradiation. This study suggests that IPL treatment is a useful strategy against photoaging, and provides evidence supporting clinical approaches with non-invasive light therapy.
| S-EPMC8003787 | biostudies-literature
Project description:ObjectiveTo investigate the efficacy, potential limitations, and biological mechanisms of UV-A1 phototherapy for skin sclerosis due to collagen deposition disorders.DesignBefore-and-after trial of UV-A1 irradiation of sclerotic skin; in vivo biochemical analyses after UV-A1 irradiation of normal skin.SettingAcademic referral center.ParticipantsPatients with morphea/scleroderma or sclerodermoid graft-vs-host disease and volunteers without skin disease. Intervention Sclerotic skin was treated with high-dose (130 J/cm(2); n = 12) or medium-dose (65 J/cm(2); n = 6) UV-A1 phototherapy 3 times per week for 14 weeks; normal skin was treated with UV-A1 irradiation at various doses and frequencies, with biopsies performed afterwards.Main outcome measuresIn sclerotic skin, induration was clinically assessed using a scoring scale. In normal skin, quantitative polymerase chain reaction was used to assess antifibrotic responses, defined as decreased type I and type III procollagen and increased matrix metalloproteinase levels.ResultsIn patients with sclerotic skin treated with high-dose UV-A1 irradiation, clinical scores for induration modestly decreased. To investigate what factors prevented further improvement (ie, complete clearance), normal skin with light pigmentation was exposed to UV-A1 irradiation (70-150 J/cm(2)) and was assessed for antifibrotic responses. A single high-dose exposure (110-150 J/cm(2)) elicited substantial antifibrotic responses and induced skin darkening. This skin darkening attenuated responses to subsequent UV-A1 exposures and was dose dependent. Thus, to minimize skin darkening, additional patients with sclerotic skin were treated with medium-dose UV-A1 phototherapy, which was no less effective than high-dose therapy.ConclusionClinical responses of sclerotic skin to UV-A1 phototherapy were modest because of UV-A1-induced skin darkening, which is photoprotective and attenuates antifibrotic responses.Trial registrationclinicaltrials.gov Identifier: NCT00129415.
| S-EPMC2956589 | biostudies-literature
Project description:Dermal macrophages containing melanin increase skin pigmentation since dermal melanin removal is slower than epidermal melanin removal. Lymphatic vessels are also involved in melanin clearance. We evaluated whether radiofrequency (RF) irradiation induced an increase in HSP90, which promotes lymphangiogenesis by activating the BRAF/MEK/ERK pathway and decreasing tyrosinase activity, in the UV-B exposed animal model. The HSP90/BRAF/MEK/ERK pathway was upregulated by RF. Tyrosinase activity and the VEGF-C/VEGFR 3/PI3K/pAKT1/2/pERK1/2 pathway, which increase lymphangiogenesis, as well as the expression of the lymphatic endothelial marker LYVE-1, were increased by RF. Additionally, the number of melanin-containing dermal macrophages, the melanin content in the lymph nodes, and melanin deposition in the skin were decreased by RF. In conclusion, RF increased HSP90/BRAF/MEK/ERK expression, which decreased tyrosinase activity and increased lymphangiogenesis to eventually promote the clearance of dermal melanin-containing macrophages, thereby decreasing skin pigmentation.
| S-EPMC8780734 | biostudies-literature
Project description:This review examines putative, yet likely critical evolutionary pressures contributing to human skin pigmentation and subsequently, depigmentation phenotypes. To achieve this, it provides a synthesis of ideas that frame contemporary thinking, without limiting the narrative to pigmentation genes alone. It examines how geography and hence the quality and quantity of UV exposure, pigmentation genes, diet-related genes, vitamins, anti-oxidant nutrients, and cultural practices intersect and interact to facilitate the evolution of human skin color. The article has a strong focus on the vitamin D-folate evolutionary model, with updates on the latest biophysical research findings to support this paradigm. This model is examined within a broad canvas that takes human expansion out of Africa and genetic architecture into account. A thorough discourse on the biology of melanization is provided (includes relationship to BH4 and DNA damage repair), with the relevance of this to the UV sensitivity of folate and UV photosynthesis of vitamin D explained in detail, including the relevance of these vitamins to reproductive success. It explores whether we might be able to predict vitamin-related gene polymorphisms that pivot metabolism to the prevailing UVR exposome within the vitamin D-folate evolutionary hypothesis context. This is discussed in terms of a primary adaptive phenotype (pigmentation/depigmentation), a secondary adaptive phenotype (flexible metabolic phenotype based on vitamin-related gene polymorphism profile), and a tertiary adaptive strategy (dietary anti-oxidants to support the secondary adaptive phenotype). Finally, alternative evolutionary models for pigmentation are discussed, as are challenges to future research in this area.
| S-EPMC10083917 | biostudies-literature
Project description:Skin sun exposure induces two protection programs: stress responses and pigmentation, the former within minutes and the latter only hours afterward. Although serving the same physiological purpose, it is not known whether and how these programs are coordinated. Here, we report that UVB exposure every other day induces significantly more skin pigmentation than the higher frequency of daily exposure, without an associated increase in stress responses. Using mathematical modeling and empirical studies, we show that the melanocyte master regulator, MITF, serves to synchronize stress responses and pigmentation and, furthermore, functions as a UV-protection timer via damped oscillatory dynamics, thereby conferring a trade-off between the two programs. MITF oscillations are controlled by multiple negative regulatory loops, one at the transcriptional level involving HIF1α and another post-transcriptional loop involving microRNA-148a. These findings support trait linkage between the two skin protection programs, which, we speculate, arose during furless skin evolution to minimize skin damage.
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Project description:Coagulase-negative staphylococcal species constitute an important part of the human skin microbiota. In particular, facultative anaerobic species such as Staphylococcus epidermidis and Staphylococcus capitis can be found on the skin of virtually every human being. Here, we applied a culture-independent amplicon sequencing approach to identify staphylococcal species on the skin of healthy human individuals. While S. epidermidis and S. capitis were found as primary residents of back skin, surprisingly, the third most abundant member was Staphylococcus saccharolyticus, a relatively unstudied species. A search of skin metagenomic datasets detected sequences identical to the genome of S. saccharolyticus in diverse skin sites, including the back, forehead, and elbow pit. Although described as a slow-growing anaerobic species, a re-evaluation of its growth behavior showed that S. saccharolyticus can grow under oxic conditions, and, in particular, in a CO2-rich atmosphere. We argue here that S. saccharolyticus was largely overlooked in previous culture-dependent and -independent studies, due to its requirement for fastidious growth conditions and the lack of reference genome sequences, respectively. Future studies are needed to unravel the microbiology and host-interacting properties of S. saccharolyticus and its role as a prevalent skin colonizer.
| S-EPMC7465461 | biostudies-literature
Project description:Skin pigmentation is associated with skin damages and skin cancers, and ultraviolet (UV) photography is used as a minimally invasive mean for the assessment of pigmentation. Since UV photography equipment is not usually available in general practice, technologies emphasizing pigmentation in color photo images are desired for daily care. We propose a new method using conditional generative adversarial networks, named UV-photo Net, to generate synthetic UV images from color photo images. Evaluations using color and UV photo image pairs taken by a UV photography system demonstrated that pigment spots were well reproduced in synthetic UV images by UV-photo Net, and some of the reproduced pigment spots were difficult to be recognized in color photo images. In the pigment spot detection analysis, the rate of pigment spot areas in cheek regions for synthetic UV images was highly correlated with the rate for UV photo images (Pearson's correlation coefficient 0.92). We also demonstrated that UV-photo Net was effective for floating up pigment spots for photo images taken by a smartphone camera. UV-photo Net enables an easy assessment of pigmentation from color photo images and will promote self-care of skin damages and early signs of skin cancers for preventive medicine.
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